[2] In 1937 he flew a newspaper service from London to Paris and then joined the Air Registration Board as a test pilot.
[2] At Farnborough he flew and tested captured German aircraft as well as carrying out operational flights with night fighter squadrons.
[2] The Avro 707 was an experimental delta-winged aircraft to gain experience for the design of the Avro Vulcan bomber, Falk's experience flying the German Messerschmitt Me 163 came in handy in what was seen as advanced and dangerous test flying.
[2] After testing the Avro 707, Falk made the first flight of the prototype Vulcan from Woodford Aerodrome on 30 August 1952.
During the 1955 Farnborough Airshow he barrel-rolled a Vulcan at the top of the post-take-off climb; although safe, he was rebuked for this manoeuvre by the organisers, but only because performing aerobatics in an aircraft weighing 69 tons and with a 99-foot wingspan was "not the done thing"!